Groundwater over-exploitation poses a severe threat to food, water and livelihood security in India, but the approach to groundwater regulation has been guided by the simplistic prescription that to achieve sustainable use, pumping must be less than recharge. This article explains the hydrological cycle and the close relationship between groundwater and surface water, and argues that the conventional notion of sustainable groundwater use is fundamentally flawed. Groundwater, soil moisture and surface water are part of a single integrated resource, and cannot be regulated independent of each other. The solution is not sustainable use or the compartmentalisation of surface and groundwater but the fair and transparent reallocation of renewable freshwater resources.